Multi-Server Installation, stuck with passwords "Not Verified"

we have ZCS running on a single server for a few days without a problem so decided to install a second Zimbra MTA.

Running ./install.sh on a new machine, it detects an existing installation... which must be the master Zimbra server, since it's a clean installation.

When the main menu displays the default entries for the Zimbra component we are installing, and after changing the "Ldap master host", "Ldap Admin password", "MTA Auth host", "Bind password for postfix ldap user" and "Bind password for amavis ldap user" entries, the passwords display "Not Verified" and the install can't be finished.

After quiting the instalation and to verify that the LDAP port isn't blocked on the master server, I,ve done with sucess a "telnet hostname 389" so this is not the origin of the problem.